标签：.text textview height line import near aaa container idg
本文以一个简单的小例子，简述在Android开发中ViewPager的常见用法，仅供学习分享使用。
ViewPager是一个支持使用者左右滑动的布局管理控件，可以通过一个实现的（适配器）PageAdapter来进行数据和页面的传递。ViewPager更多时候会和Fragment一起使用，方便管理各个页面的生命周期。
图片轮播如下所示：
xml布局代码
1 <?xml version="1.0" encoding="utf-8"?> 2 <RelativeLayout 3 xmlns:android="http://schemas.android.com/apk/res/android" 4 xmlns:tools="http://schemas.android.com/tools" 5 android:layout_width="match_parent" 6 android:layout_height="match_parent" 7 tools:context="com.hex.demoviewpager.MainActivity"> 8 <android.support.v4.view.ViewPager 9 android:id="@+id/vp_info" 10 android:scrollIndicators="bottom" 11 android:layout_width="match_parent" 12 android:layout_height="match_parent"> 13 </android.support.v4.view.ViewPager> 14 <TextView 15 android:id="@+id/tv_title" 16 android:layout_alignBottom="@id/vp_info" 17 android:layout_centerHorizontal="true" 18 android:textSize="20dp" 19 android:text="aaaa" 20 android:layout_marginBottom="30dp" 21 android:layout_width="wrap_content" 22 android:layout_height="wrap_content"/> 23 <LinearLayout 24 android:id="@+id/ll_Indicator" 25 android:layout_alignBottom="@id/vp_info" 26 android:layout_centerHorizontal="true" 27 android:gravity="center" 28 android:orientation="horizontal" 29 android:layout_width="200dp" 30 android:layout_height="wrap_content"> 31 32 </LinearLayout> 33 <Button 34 android:id="@+id/bn_go" 35 android:text="@string/go" 36 android:layout_alignParentTop="true" 37 android:layout_width="wrap_content" 38 android:layout_height="wrap_content"/> 39 </RelativeLayout>
Java代码（图片轮播）
1 package com.hex.demoviewpager; 2 3 import android.content.Intent; 4 import android.support.v4.view.PagerAdapter; 5 import android.support.v4.view.ViewPager; 6 import android.support.v7.app.ActionBar; 7 import android.support.v7.app.AppCompatActivity; 8 import android.os.Bundle; 9 import android.util.Log; 10 import android.view.View; 11 import android.view.ViewGroup; 12 import android.widget.Button; 13 import android.widget.ImageView; 14 import android.widget.LinearLayout; 15 import android.widget.TextView; 16 17 public class MainActivity extends AppCompatActivity { 18 19 private ViewPager mViewPager; 20 int[] imgs; 21 String[] titles; 22 TextView tvTitle; 23 LinearLayout llIndicator; 24 Button mGo; 25 @Override 26 protected void onCreate(Bundle savedInstanceState) { 27 super.onCreate(savedInstanceState); 28 setContentView(R.layout.activity_main); 29 mViewPager= (ViewPager) this.findViewById(R.id.vp_info); 30 imgs=new int[]{R.drawable.s01,R.drawable.s02,R.drawable.s03,R.drawable.s04,R.drawable.s05}; 31 titles=new String[]{"第一张图","第二张图","第三张图","第四张图","第五张图"}; 32 tvTitle= (TextView) this.findViewById(R.id.tv_title); 33 //构造适配器并赋值 34 MyAdapter adapter=new MyAdapter(); 35 mViewPager.setAdapter(adapter); 36 //初始化第一个标题 37 tvTitle.setText(titles[0]); 38 //初始化指示器 39 llIndicator = (LinearLayout) this.findViewById(R.id.ll_Indicator); 40 setIndicator(0); 41 //设置页面切换监听事件 42 mViewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 43 /** 44 * 页面被选中 45 * @param position 46 */ 47 @Override 48 public void onPageSelected(int position) { 49 Log.v("DemoViewPager","当前是："+titles[position]); 50 tvTitle.setText(titles[position]); 51 //设置指示器 52 llIndicator.removeAllViews(); 53 setIndicator(position); 54 } 55 }); 56 //页面跳转 57 mGo= (Button) this.findViewById(R.id.bn_go); 58 mGo.setOnClickListener(new View.OnClickListener() { 59 @Override 60 public void onClick(View v) { 61 Intent intent=new Intent(MainActivity.this,Main2Activity.class); 62 startActivity(intent); 63 } 64 }); 65 } 66 67 /** 68 * 设置指示器 69 * @param position 70 */ 71 private void setIndicator(int position){ 72 for(int i=0;i<imgs.length;i++) { 73 ImageView imgIndicatior = new ImageView(MainActivity.this); 74 LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(10, 10); 75 layoutParams.leftMargin = 10; 76 layoutParams.rightMargin = 10; 77 imgIndicatior.setLayoutParams(layoutParams); 78 if (i == position) { 79 imgIndicatior.setImageResource(R.drawable.dot1); 80 } else { 81 imgIndicatior.setImageResource(R.drawable.dot0); 82 } 83 llIndicator.addView(imgIndicatior); 84 } 85 } 86 87 /* 88 描述：自定义一适配器 89 */ 90 class MyAdapter extends PagerAdapter 91 { 92 93 @Override 94 public int getCount() { 95 return imgs == null ? 0 : imgs.length; 96 } 97 98 /** 99 * 是否需要重新加载子视图 100 * @param view 101 * @param object 102 * @return 103 */ 104 @Override 105 public boolean isViewFromObject(View view, Object object) { 106 return view == object; 107 } 108 109 @Override 110 public void destroyItem(ViewGroup container, int position, Object object) { 111 //container.removeViewAt(position); 112 container.removeView((View)object); 113 } 114 115 /** 116 * 生成子视图 117 * @param container 118 * @param position 119 * @return 120 */ 121 @Override 122 public Object instantiateItem(ViewGroup container, int position) { 123 ImageView img=new ImageView(container.getContext()); 124 img.setImageResource(imgs[position]); 125 container.addView(img); 126 return img; 127 } 128 129 @Override 130 public CharSequence getPageTitle(int position) { 131 return titles[position]; 132 } 133 } 134 }
Java代码（Fragment滑动）
1 package com.hex.demoviewpager; 2 3 import android.support.v4.app.Fragment; 4 import android.support.v4.app.FragmentActivity; 5 import android.support.v4.app.FragmentManager; 6 import android.support.v4.app.FragmentPagerAdapter; 7 import android.support.v4.view.ViewPager; 8 import android.support.v7.app.AppCompatActivity; 9 import android.os.Bundle; 10 import android.util.Log; 11 import android.widget.ImageView; 12 import android.widget.LinearLayout; 13 14 import java.util.ArrayList; 15 import java.util.List; 16 17 public class Main2Activity extends FragmentActivity { 18 19 private ViewPager mViewPager2; 20 private List<Fragment> mList; 21 LinearLayout llIndicator2; 22 @Override 23 protected void onCreate(Bundle savedInstanceState) { 24 super.onCreate(savedInstanceState); 25 setContentView(R.layout.activity_main2); 26 mViewPager2= (ViewPager) this.findViewById(R.id.vp_info2); 27 mList=new ArrayList<Fragment>(); 28 for(int i=0;i<5;i++){ 29 ContentFragment fragment=ContentFragment.newInstance("第 "+i+" 个Fragment"); 30 mList.add(fragment); 31 } 32 FragmentManager manager = getSupportFragmentManager(); 33 MyAdapter2 adapter2=new MyAdapter2(manager); 34 mViewPager2.setAdapter(adapter2); 35 //初始化指示器 36 llIndicator2 = (LinearLayout) this.findViewById(R.id.ll_Indicator2); 37 setIndicator(0); 38 //设置页面切换监听事件 39 mViewPager2.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { 40 /** 41 * 页面被选中 42 * @param position 43 */ 44 @Override 45 public void onPageSelected(int position) { 46 //设置指示器 47 llIndicator2.removeAllViews(); 48 setIndicator(position); 49 } 50 }); 51 } 52 53 /** 54 * 设置指示器 55 * @param position 56 */ 57 private void setIndicator(int position){ 58 for(int i=0;i<mList.size();i++) { 59 ImageView imgIndicatior = new ImageView(Main2Activity.this); 60 LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(10, 10); 61 layoutParams.leftMargin = 10; 62 layoutParams.rightMargin = 10; 63 imgIndicatior.setLayoutParams(layoutParams); 64 if (i == position) { 65 imgIndicatior.setImageResource(R.drawable.dot1); 66 } else { 67 imgIndicatior.setImageResource(R.drawable.dot0); 68 } 69 llIndicator2.addView(imgIndicatior); 70 } 71 } 72 73 /** 74 * 结合Fragement的适配器 75 */ 76 class MyAdapter2 extends FragmentPagerAdapter{ 77 78 public MyAdapter2(FragmentManager fm) { 79 super(fm); 80 81 } 82 83 @Override 84 public int getCount() { 85 return mList==null ? 0:mList.size(); 86 } 87 88 @Override 89 public Fragment getItem(int position) { 90 return mList.get(position); 91 } 92 } 93 }
ViewPager支持的Fragment也是android.support.v4.app包中的Fragment，需要调用的Activity也是需要继承android.support.v4.app.FragmentActivity 。ViewPager中的图片指示器是用LinearLayout中图片实现的。
标签：.text textview height line import near aaa container idg
原文地址：https://www.cnblogs.com/hsiang/p/10328332.html
